Apollo 8, the second manned spaceflight mission in the United States
Apollo space program, was launched on December 21, 1968, and became
the first manned spacecraft to leave
EarthEarth orbit, reach the Earth's
Moon, orbit it and return safely to Earth. The three-astronaut crew
— Commander Frank Borman, Command Module Pilot James Lovell, and
Lunar Module Pilot
William AndersWilliam Anders — became the first humans to:
travel beyond low
EarthEarth orbit; see
EarthEarth as a whole planet; enter the
gravity well of another celestial body (Earth's moon); orbit another
celestial body (Earth's moon); directly see the far side of the Moon
with their own eyes; witness an Earthrise; escape the gravity of
another celestial body (Earth's moon); and re-enter the gravitational
well of Earth. The 1968 mission, the third flight of the Saturn V
rocket and that rocket's first crewed launch, was also the first human
spaceflight launch from the Kennedy Space Center, Florida, located
adjacent to Cape Canaveral Air Force Station.
Originally planned as a second Lunar Module/Command Module test in an
elliptical medium
EarthEarth orbit in early 1969, the mission profile was
changed in August 1968 to a more ambitious Command Module-only lunar
orbital flight to be flown in December, because the Lunar Module was
not yet ready to make its first flight. This meant Borman's crew was
scheduled to fly two to three months sooner than originally planned,
leaving them a shorter time for training and preparation, thus placing
more demands than usual on their time and discipline.
Apollo 8Apollo 8 took 68 hours (2.8 days) to travel the distance to the Moon.
It orbited ten times over the course of 20 hours, during which the
crew made a Christmas Eve television broadcast where they read the
first 10 verses from the
BookBook of Genesis. At the time, the broadcast
was the most watched TV program ever. Apollo 8's successful mission
paved the way for
Apollo 11Apollo 11 to fulfill U.S. President John F.
Kennedy's goal of landing a man on the
MoonMoon before the end of the
1960s. The
Apollo 8Apollo 8 astronauts returned to
EarthEarth on December 27, 1968,
when their spacecraft splashed down in the Northern Pacific Ocean. The
crew members were named Time magazine's "Men of the Year" for 1968
upon their return.

Lunar Module Pilot was the official title used for the third pilot
position in Block II missions, regardless of whether the LM spacecraft
was present or not.

Lovell was originally the CMP on the back-up crew, with Michael
Collins as the prime crew's CMP. However, Collins was replaced in July
1968, after suffering a cervical disc herniation that required surgery
to repair.[6]
This crew was unique among pre-shuttle era missions in that the
commander was not the most experienced member of the crew, as Lovell
had flown twice before, on Gemini VII and Gemini XII. This was also
the first case of the rarity of an astronaut who had commanded a
spaceflight mission subsequently flying as a non-commander, as Lovell
had previously commanded Gemini XII.
Backup crew[edit]

Position
Astronaut[7]

Commander
Neil A. Armstrong

Command Module Pilot
Edwin E. Aldrin, Jr.

Lunar Module Pilot
Fred W. Haise, Jr.

On a lunar mission, the Command Module Pilot (CMP) was assigned the
role of navigator, while the Lunar Module Pilot (LMP) was assigned the
role of flight engineer, responsible for monitoring all spacecraft
systems, even if the flight didn't include a Lunar Module.[8]
Edwin "Buzz" Aldrin was originally the backup LMP. When Lovell was
rotated to the prime crew, no one with experience on CSM-103 (the
specific spacecraft used for the mission) was available, so Aldrin was
moved to CMP and
Fred HaiseFred Haise brought in as backup LMP. Neil Armstrong
went on to command Apollo 11, where Aldrin was returned to the LMP
position and Collins was assigned as CMP. Haise was rotated out of the
crew and onto the backup crew of
Apollo 11Apollo 11 as LMP.
Mission control[edit]
The Earth-based mission control teams for Apollo 8 consisted of
astronauts assigned to the support crew, as well as non-astronaut
flight directors and their staffs. The support crew members were not
trained to fly the mission, but were able to stand in for astronauts
in meetings and be involved in the minutiae of mission planning, while
the prime and backup crews trained. They also served as CAPCOMs during
the mission. For Apollo 8, these crew members included astronauts
John S. Bull, Vance D. Brand, Gerald P. Carr, and Ken Mattingly.[9]
The mission control teams on
EarthEarth rotated in three shifts, each led
by a flight director. The directors for Apollo 8 included
Clifford E. Charlesworth (Green team),
Glynn LunneyGlynn Lunney (Black team), and
Milton WindlerMilton Windler (Maroon team).[10]
Mission insignia[edit]

The triangular shape of the insignia symbolizes the shape of the
Apollo Command Module (CM). It shows a red figure-8 looping around the
EarthEarth and
MoonMoon representing the mission number as well as the
circumlunar nature of the mission. On the red number 8 are the names
of the three astronauts.[11]
The initial design of the insignia was developed by Jim Lovell. Lovell
reportedly sketched the initial design while riding in the backseat of
a T-38 flight from
CaliforniaCalifornia to Houston, shortly after learning of
the re-designation of the flight to become a lunar-orbital mission.
The graphic design of the insignia was done by
HoustonHouston artist and
animator William Bradley.[11]
Planning[edit]
Main article: List of Apollo mission types
Apollo 4Apollo 4 and
Apollo 6Apollo 6 had been "A" missions, unmanned tests of the
Saturn VSaturn V launch vehicle using an unmanned Block I production
model of the Apollo Command and Service Module in
EarthEarth orbit. Apollo
7, scheduled for October 1968, would be a manned Earth-orbit flight of
the CSM, completing the objectives for Mission "C".

Apollo CSM diagram

Further missions depended on the readiness of the Lunar Module. Apollo
8 was planned as the "D" mission, to test the LM in a low
EarthEarth orbit
in December 1968 by James McDivitt,
David ScottDavid Scott and Russell
Schweickart, while Borman's crew would fly the "E" mission, a more
rigorous LM test in an elliptical medium
EarthEarth orbit as Apollo 9, in
early 1969.
But production of the LM fell behind schedule, and when Apollo 8's LM
arrived at the
Kennedy Space CenterKennedy Space Center in June 1968, significant defects
were discovered, leading Grumman, the lead contractor for the LM, to
predict that the first mission-ready LM would not be ready until at
least February 1969. This would mean delaying the "D" and subsequent
missions, endangering the program's goal of a lunar landing before the
end of 1969.[8][12]
George Low, the Manager of the Apollo
SpacecraftSpacecraft Program Office,
proposed a solution in August to keep the program on track despite the
LM delay. Since the
Command/Service ModuleCommand/Service Module (CSM) would be ready three
months before the Lunar Module, a CSM-only mission could be flown in
December 1968. Instead of just repeating the "C" mission flight of
Apollo 7, this CSM could be sent all the way to the Moon, with
the possibility of entering a lunar orbit. The new mission would also
allow
NASANASA to test lunar landing procedures that would otherwise have
to wait until Apollo 10, the scheduled "F" mission.[12] This also
meant that the medium
EarthEarth orbit "E" mission could be dispensed with.
The net result was that only the "D" mission had to be delayed.

The first stage of AS-503 being erected in the Vertical Assembly
Building (VAB) on February 1, 1968

Almost every senior manager at
NASANASA agreed with this new mission,
citing both confidence in the hardware and personnel, and the
potential for a significant morale boost provided by a circumlunar
flight. The only person who needed some convincing was James E. Webb,
the
NASANASA administrator. With the rest of his agency in support of the
new mission, Webb eventually approved the mission change. The mission
was officially changed from a "D" mission to a "C-Prime" lunar-orbit
mission, but was still referred to in press releases as an Earth-orbit
mission at Webb's direction.[13] No public announcement was made about
the change in mission until November 12, three weeks after Apollo 7's
successful Earth-orbit mission and less than 40 days before
launch.[14]
With the change in mission for Apollo 8, Director of Flight Crew
Operations
Deke SlaytonDeke Slayton decided to swap the crews of the D and E
missions. This swap also meant a swap of spacecraft, requiring
Borman's crew to use CSM-103, while McDivitt's crew would use
CSM-104.[12][15]
On September 9, the crew entered the simulators to begin their
preparation for the flight. By the time the mission flew, the crew had
spent seven hours training for every actual hour of flight.
Although all crew members were trained in all aspects of the mission,
it was necessary to specialize. Borman, as commander, was given
training on controlling the spacecraft during the re-entry. Lovell was
trained on navigating the spacecraft in case communication was lost
with the Earth. Anders was placed in charge of checking that the
spacecraft was in working order.[8]
Added pressure on the
Apollo programApollo program to make its 1969 landing goal was
provided by the Soviet Union's flight of some living creatures,
including Russian tortoises, in a cislunar loop around the
MoonMoon on
Zond 5Zond 5 and return to
EarthEarth on September 21.[16] There was speculation
within
NASANASA and the press that they might be preparing to launch
cosmonauts on a similar circumlunar mission before the end of
1968.[17]
The
Apollo 8Apollo 8 crew, now living in the crew quarters at Kennedy Space
Center, received a visit from
Charles LindberghCharles Lindbergh and his wife, Anne
Morrow Lindbergh, the night before the launch.[18] They talked about
how, before his 1927 flight, Lindbergh had used a piece of string to
measure the distance from New York City to Paris on a globe and from
that calculated the fuel needed for the flight. The total was a tenth
of the amount that the Saturn V would burn every second.[19] The
next day, the Lindberghs watched the launch of Apollo 8 from a
nearby dune.[19]
Saturn V[edit]
Main article: Saturn V

The Saturn V rocket used by Apollo 8 was designated SA-503,
or the "03rd" model of the Saturn V ("5") Rocket to be used in
the Saturn-Apollo ("SA") program. When it was erected in the Vertical
Assembly Building on December 20, 1967, it was thought that the rocket
would be used for an unmanned Earth-orbit test flight carrying a
boilerplate Command/Service Module. Apollo 6 had suffered several
major problems during its April 1968 flight, including severe pogo
oscillation during its first stage, two second stage engine failures,
and a third stage that failed to reignite in orbit. Without assurances
that these problems had been rectified,
NASANASA administrators could not
justify risking a manned mission until additional unmanned test
flights proved that the Saturn V was ready.[20][21]
Teams from the
Marshall Space Flight CenterMarshall Space Flight Center (MSFC) went to work on the
problems. Of primary concern was the pogo oscillation, which would not
only hamper engine performance, but could exert significant g-forces
on a crew. A task force of contractors,
NASANASA agency representatives,
and MSFC researchers concluded that the engines vibrated at a
frequency similar to the frequency at which the spacecraft itself
vibrated, causing a resonance effect that induced oscillations in the
rocket. A system using helium gas to absorb some of these vibrations
was installed.[20]
Of equal importance was the failure of three engines during flight.
Researchers quickly determined that a leaking hydrogen fuel line
ruptured when exposed to vacuum, causing a loss of fuel pressure in
engine two. When an automatic shutoff attempted to close the liquid
hydrogen valve and shut down engine two, it accidentally shut down
engine three's liquid oxygen due to a miswired connection. As a
result, engine three failed within one second of engine two's
shutdown. Further investigation revealed the same problem for the
third-stage engine—a faulty igniter line. The team modified the
igniter lines and fuel conduits, hoping to avoid similar problems on
future launches.[20]
The teams tested their solutions in August 1968 at the Marshall Space
Flight Center. A Saturn stage IC was equipped with shock absorbing
devices to demonstrate the team's solution to the problem of pogo
oscillation, while a Saturn Stage II was retrofitted with
modified fuel lines to demonstrate their resistance to leaks and
ruptures in vacuum conditions. Once
NASANASA administrators were convinced
that the problems were solved, they gave their approval for a manned
mission using SA-503.[20][22]
The Apollo 8 spacecraft was placed on top of the rocket on
September 21 and the rocket made the slow 3-mile (5 km) journey
to the launch pad on October 9.[23] Testing continued all through
December until the day before launch, including various levels of
readiness testing from December 5 through 11. Final testing of
modifications to address the problems of pogo oscillation, ruptured
fuel lines, and bad igniter lines took place on December 18, a mere
three days before the scheduled launch.[20]
Mission[edit]
Parameter summary[edit]

As the first manned spacecraft to orbit more than one celestial body,
Apollo 8's profile had two different sets of orbital parameters,
separated by a translunar injection maneuver.
Apollo lunar missions would begin with a nominal 100-nautical-mile
(185.2 km) circular
EarthEarth parking orbit.
Apollo 8Apollo 8 was launched
into an initial orbit with an apogee of 99.99 nautical miles
(185.18 km) and a perigee of 99.57 nautical miles
(184.40 km), with an inclination of 32.51° to the Equator, and
an orbital period of 88.19 minutes. Propellant venting increased
the apogee by 6.4 nautical miles (11.9 km) over the 2 hours,
44 minutes and 30 seconds spent in the parking orbit.[22]
This was followed by a Trans-Lunar Injection (TLI) burn of the S-IVB
third stage for 318 seconds, accelerating the 63,650 lb
(28,870 kg)
Command/Service ModuleCommand/Service Module and 19,900 lb
(9,000 kg) LM test article from an orbital velocity of 25,567
feet per second (7,793 m/s) to the injection velocity of
35,505 ft/s (10,822 m/s),[22][2] which set a record for the
highest speed, relative to Earth, that humans had ever traveled.[25]
This speed was slightly less than the Earth's escape velocity of
36,747 feet per second (11,200 m/s), but put
Apollo 8Apollo 8 into an
elongated elliptical
EarthEarth orbit, to a point where the Moon's gravity
would capture it.[26]
The standard lunar orbit for Apollo missions was planned as a nominal
60-nautical-mile (110 km) circular orbit above the Moon's
surface. Initial lunar orbit insertion was an ellipse with a perilune
of 60.0 nautical miles (111.1 km) and an apolune of 168.5
nautical miles (312.1 km), at an inclination of 12° from the
lunar equator. This was then circularized at 60.7 nautical miles
(112.4 km) by 59.7 nautical miles (110.6 km), with an
orbital period of 128.7 minutes. The effect of lunar mass
concentrations ("masscons") on the orbit was found to be greater than
initially predicted; over the course of the ten lunar orbits lasting
twenty hours, the orbital distance was perturbated to 63.6 nautical
miles (117.8 km) by 58.6 nautical miles (108.5 km).[22]
Apollo 8Apollo 8 achieved a maximum distance from
EarthEarth of 203,752 nautical
miles (234,474 statute miles; 377,349 kilometers).[22]
Launch and trans-lunar injection[edit]

Apollo 8 during launch, with a double exposure of the Moon, which
was not visible at the time

Apollo 8 launched at 7:51:00 a.m. Eastern Standard Time on
December 21, 1968, using the Saturn V's three stages to achieve
EarthEarth orbit.[22] The
S-ICS-IC first stage impacted the
Atlantic OceanAtlantic Ocean at
30°12′N 74°7′W﻿ / ﻿30.200°N 74.117°W﻿ / 30.200;
-74.117﻿ (
Apollo 8Apollo 8S-ICS-IC impact) and the
S-IIS-II second stage at
31°50′N 37°17′W﻿ / ﻿31.833°N 37.283°W﻿ / 31.833;
-37.283﻿ (
Apollo 8Apollo 8S-IIS-II impact).[19][22] The
S-IVBS-IVB third stage
injected the craft into
EarthEarth orbit, but remained attached to later
perform the trans-lunar injection (TLI) burn that put the spacecraft
on a trajectory to the Moon.
Once the vehicle reached
EarthEarth orbit, both the crew and
HoustonHouston flight
controllers spent the next 2 hours and 38 minutes checking
that the spacecraft was in proper working order and ready for TLI. The
proper operation of the
S-IVBS-IVB third stage of the rocket was crucial:
in the last unmanned test, it had failed to re-ignite for TLI.[25]
During the flight, three fellow astronauts served on the ground as
Capsule Communicators (usually referred to as "CAPCOMs") on a rotating
schedule. The CAPCOMs were the only people who regularly communicated
with the crew. Michael Collins was the first CAPCOM on duty and at
2 hours, 27 minutes and 22 seconds after launch
radioed, "Apollo 8. You are Go for TLI."[27] This communication
signified that Mission Control had given official permission for
Apollo 8 to go to the Moon. Over the next 12 minutes before
the TLI burn, the Apollo 8 crew continued to monitor the
spacecraft and the S-IVB. The engine ignited on time and performed the
TLI burn perfectly.
After the
S-IVBS-IVB had performed its required tasks, it was jettisoned.
The crew then rotated the spacecraft to take some photographs of the
spent stage and then practiced flying in formation with it. As the
crew rotated the spacecraft, they had their first views of the Earth
as they moved away from it. This marked the first time humans could
view the whole
EarthEarth at once.[25] Borman became worried that the S-IVB
was staying too close to the
Command/Service ModuleCommand/Service Module and suggested to
Mission Control that the crew perform a separation maneuver. Mission
Control first suggested pointing the spacecraft towards
EarthEarth and
using the Reaction Control System (RCS) thrusters on the Service
Module (SM) to add 3 ft/s (0.91 m/s) away from the Earth,
but Borman did not want to lose sight of the S-IVB. After discussion,
the crew and Mission Control decided to burn in this direction, but at
9 ft/s (2.7 m/s) instead.[22] These discussions put the crew
an hour behind their flight plan.[25]

Five hours after launch, Mission Control sent a command to the
S-IVBS-IVB booster to vent its remaining fuel through its engine bell to
change the booster's trajectory. This
S-IVBS-IVB would then pass the Moon
and enter into a solar orbit, posing no further hazard to
Apollo 8. The
S-IVBS-IVB subsequently went into a
0.99-by-0.92-astronomical-unit (148 by 138 Gm) solar orbit with
an inclination of 23.47° from the plane of the ecliptic, and an
orbital period of 340.80 days.[22] After the insertion into
trans-Lunar orbit, the Saturn IVB third stage became a derelict
object. It will continue to orbit the Sun for many years.[28]
The Apollo 8 crew were the first humans to pass through the Van
Allen radiation belts, which extend up to 15,000 miles
(24,000 km) from Earth. Scientists predicted that passing through
the belts quickly at the spacecraft's high speed would cause a
radiation dosage of no more than a chest X-ray, or 1 milligray (during
a year, the average human receives a dose of
2 to 3 mGy). To record the actual radiation dosages,
each crew member wore a Personal Radiation
DosimeterDosimeter that transmitted
data to
EarthEarth as well as three passive film dosimeters that showed the
cumulative radiation experienced by the crew. By the end of the
mission, the crew experienced an average radiation dose of 1.6
mGy.[29]
Lunar trajectory[edit]

The first image ever taken by humans of the whole Earth, probably
photographed by William Anders;[30] South is up with South America in
the middle

Jim Lovell's main job as Command Module Pilot was as navigator.
Although Mission Control performed all the actual navigation
calculations, it was necessary to have a crew member serving as
navigator so that the crew could return to
EarthEarth in case of loss of
communication with Mission Control. Lovell navigated by star sightings
using a sextant built into the spacecraft, measuring the angle between
a star and the Earth's (or the Moon's) horizon. This task was
difficult, because a large cloud of debris around the spacecraft,
formed by the venting S-IVB, made it hard to distinguish the stars.
By seven hours into the mission, the crew was about one hour and 40
minutes behind flight plan, because of the problems in moving away
from the
S-IVBS-IVB and Lovell's obscured star sightings. The crew now
placed the spacecraft into Passive Thermal Control (PTC), also called
"barbecue roll", in which the spacecraft rotated about once per hour
around its long axis to ensure even heat distribution across the
surface of the spacecraft. In direct sunlight, the spacecraft could be
heated to over 200 °C (392 °F) while the parts in shadow
would be −100 °C (−148 °F). These temperatures could
cause the heat shield to crack and propellant lines to burst. Because
it was impossible to get a perfect roll, the spacecraft swept out a
cone as it rotated. The crew had to make minor adjustments every half
hour as the cone pattern got larger and larger.[31]
The first mid-course correction came 11 hours into the flight. Testing
on the ground had shown that the
Service Propulsion SystemService Propulsion System (SPS)
engine had a small chance of exploding when burned for long periods
unless its combustion chamber was "coated" first. Burning the engine
for a short period would accomplish coating. This first correction
burn was only 2.4 seconds and added about 20.4 ft/s
(6.2 m/s) velocity prograde (in the direction of travel).[22]
This change was less than the planned 24.8 ft/s (7.6 m/s),
because of a bubble of helium in the oxidizer lines, which caused
unexpectedly low propellant pressure. The crew had to use the small
RCS thrusters to make up the shortfall. Two later planned mid-course
corrections were canceled because the Apollo 8 trajectory was
found to be perfect.[31]
Eleven hours into the flight, the crew had been awake for more than 16
hours. Before launch,
NASANASA had decided that at least one crew member
should be awake at all times to deal with problems that might arise.
Borman started the first sleep shift, but found sleeping difficult
because of the constant radio chatter and mechanical noises.[31]
About an hour after starting his sleep shift, Borman obtained
permission from ground control to take a Seconal sleeping pill. The
pill had little effect. Borman eventually fell asleep, and then awoke
feeling ill. He vomited twice and had a bout of diarrhea; this left
the spacecraft full of small globules of vomit and feces, which the
crew cleaned up as well as they could. Borman initially did not want
everyone to know about his medical problems, but Lovell and Anders
wanted to inform Mission Control. The crew decided to use the Data
Storage Equipment (DSE), which could tape voice recordings and
telemetry and dump them to Mission Control at high speed. After
recording a description of Borman's illness they asked Mission Control
to check the recording, stating that they "would like an evaluation of
the voice comments".[32]
The Apollo 8 crew and Mission Control medical personnel held a
conference using an unoccupied second-floor control room (there were
two identical control rooms in Houston, on the second and third
floors, only one of which was used during a mission). The conference
participants concluded that there was little to worry about and that
Borman's illness was either a 24-hour flu, as Borman thought, or a
reaction to the sleeping pill.[33] Researchers now believe that he was
suffering from space-adaptation syndrome, which affects about a third
of astronauts during their first day in space as their vestibular
system adapts to weightlessness.[34] Space-adaptation syndrome had not
occurred on previous spacecraft (Mercury and Gemini), because those
astronauts couldn't move freely in the small cabins of those
spacecraft. The increased cabin space in the Apollo Command Module
afforded astronauts greater freedom of movement, contributing to
symptoms of space sickness for Borman and, later, astronaut Russell
Schweickart during Apollo 9.[35]

Film of the crew taken while they were in orbit around the Moon; Frank
Borman is in the center

The cruise phase was a relatively uneventful part of the flight,
except for the crew checking that the spacecraft was in working order
and that they were on course. During this time,
NASANASA scheduled a
television broadcast at 31 hours after launch. The Apollo 8
crew used a 2 kg camera that broadcast in black-and-white only,
using a Vidicon tube. The camera had two lenses, a very wide-angle
(160°) lens, and a telephoto (9°) lens.[25]
During this first broadcast, the crew gave a tour of the spacecraft
and attempted to show how the
EarthEarth appeared from space. However,
difficulties aiming the narrow-angle lens without the aid of a monitor
to show what it was looking at made showing the
EarthEarth impossible.
Additionally, the
EarthEarth image became saturated by any bright source
without proper filters. In the end, all the crew could show the people
watching back on
EarthEarth was a bright blob. After broadcasting for
17 minutes, the rotation of the spacecraft took the high-gain
antenna out of view of the receiving stations on
EarthEarth and they ended
the transmission with Lovell wishing his mother a happy birthday.[25]
By this time, the crew had completely abandoned the planned sleep
shifts. Lovell went to sleep 32½ hours into the
flight—3½ hours before he had planned to. A short while later,
Anders also went to sleep after taking a sleeping pill.[25]
The crew was unable to see the
MoonMoon for much of the outward cruise.
Two factors made the
MoonMoon almost impossible to see from inside the
spacecraft: three of the five windows fogging up due to out-gassed
oils from the silicone sealant, and the attitude required for the PTC.
It was not until the crew had gone behind the
MoonMoon that they would be
able to see it for the first time.[19]
Apollo 8 made a second television broadcast at 55 hours into
the flight. This time, the crew rigged up filters meant for the still
cameras so they could acquire images of the
EarthEarth through the
telephoto lens. Although difficult to aim, as they had to maneuver the
entire spacecraft, the crew was able to broadcast back to
EarthEarth the
first television pictures of the Earth. The crew spent the
transmission describing the
EarthEarth and what was visible and the colors
they could see. The transmission lasted 23 minutes.[25]
Lunar sphere of influence[edit]
At about 55 hours and 40 minutes into the flight, the crew
of Apollo 8 became the first humans to enter the gravitational
sphere of influence of another celestial body.[22] In other words, the
effect of the Moon's gravitational force on Apollo 8 became
stronger than that of the Earth. At the time it happened,
Apollo 8 was 38,759 miles (62,377 km) from the
MoonMoon and had
a speed of 3,990 ft/s (1,220 m/s) relative to the Moon.[22]
This historic moment was of little interest to the crew since they
were still calculating their trajectory with respect to the launch pad
at Kennedy Space Center. They would continue to do so until they
performed their last mid-course correction, switching to a reference
frame based on ideal orientation for the second engine burn they would
make in lunar orbit. It was only 13 hours until they would be in
lunar orbit.[36]
The last major event before Lunar
OrbitOrbit Insertion (LOI) was a second
mid-course correction. It was in retrograde (against direction of
travel) and slowed the spacecraft down by 2.0 ft/s
(0.61 m/s), effectively lowering the closest distance that the
spacecraft would pass the moon.[22] At exactly 61 hours after
launch, about 24,200 miles (38,900 km) from the Moon, the crew
burned the RCS for 11 seconds. They would now pass 71.7 miles
(115.4 km) from the lunar surface.[19][22]
At 64 hours into the flight, the crew began to prepare for Lunar
OrbitOrbit Insertion-1 (LOI-1). This maneuver had to be performed
perfectly, and due to orbital mechanics had to be on the far side of
the Moon, out of contact with the Earth. After Mission Control was
polled for a "go/no go" decision, the crew was told at 68 hours,
they were Go and "riding the best bird we can find".[37] Lovell
replied, "We'll see you on the other side", and for the first time in
history, humans travelled behind the
MoonMoon and out of radio contact
with the Earth.[36][37][38]
With 10 minutes before the LOI-1, the crew began one last check
of the spacecraft systems and made sure that every switch was in the
correct place. At that time, they finally got their first glimpses of
the Moon. They had been flying over the unlit side, and it was Lovell
who saw the first shafts of sunlight obliquely illuminating the lunar
surface. The LOI burn was only two minutes away, so the crew had
little time to appreciate the view.[36]
Lunar orbit[edit]
The SPS ignited at 69 hours, 8 minutes, and 16 seconds
after launch and burned for 4 minutes and 7 seconds, placing
the Apollo 8 spacecraft in orbit around the Moon. The crew
described the burn as being the longest four minutes of their lives.
If the burn had not lasted exactly the correct amount of time, the
spacecraft could have ended up in a highly elliptical lunar orbit or
even flung off into space. If it lasted too long they could have
struck the Moon. After making sure the spacecraft was working, they
finally had a chance to look at the Moon, which they would orbit for
the next 20 hours.[39]
On Earth, Mission Control continued to wait. If the crew had not
burned the engine or the burn had not lasted the planned length of
time, the crew would appear early from behind the Moon. However, this
time came and went without Apollo 8 reappearing. Exactly at the
calculated moment, the signal was received from the spacecraft,
indicating it was in a 193.3-by-69.5-mile (311.1 by 111.8 km)
orbit about the Moon.[39]
After reporting on the status of the spacecraft, Lovell gave the first
description of what the lunar surface looked like:

The
MoonMoon is essentially grey, no color; looks like plaster of Paris or
sort of a grayish beach sand. We can see quite a bit of detail. The
Sea of Fertility doesn't stand out as well here as it does back on
Earth. There's not as much contrast between that and the surrounding
craters. The craters are all rounded off. There's quite a few of them,
some of them are newer. Many of them look like—especially the round
ones—look like hit by meteorites or projectiles of some sort.
Langrenus is quite a huge crater; it's got a central cone to it. The
walls of the crater are terraced, about six or seven different
terraces on the way down.[40]

A portion of the lunar far side as seen from Apollo 8

Lovell continued to describe the terrain they were passing over. One
of the crew's major tasks was reconnaissance of planned future landing
sites on the Moon, especially one in
Mare TranquillitatisMare Tranquillitatis that would
be the Apollo 11 landing site. The launch time of Apollo 8
had been chosen to give the best lighting conditions for examining the
site. A film camera had been set up in one of the spacecraft windows
to record a frame every second of the
MoonMoon below. Bill Anders spent
much of the next 20 hours taking as many photographs as possible
of targets of interest. By the end of the mission the crew had taken
700 photographs of the
MoonMoon and 150 of the Earth.[19]
Throughout the hour that the spacecraft was in contact with Earth,
Borman kept asking how the data for the SPS looked. He wanted to make
sure that the engine was working and could be used to return early to
the
EarthEarth if necessary. He also asked that they receive a "go/no go"
decision before they passed behind the
MoonMoon on each orbit.[40]
As they reappeared for their second pass in front of the Moon, the
crew set up the equipment to broadcast a view of the lunar surface.
Anders described the craters that they were passing over. At the end
of this second orbit they performed the 11-second LOI-2 burn of the
SPS to circularize the orbit to 70.0 by 71.3 miles (112.7 by
114.7 km).[39][40]
Through the next two orbits, the crew continued to keep check of the
spacecraft and to observe and photograph the Moon. During the third
pass, Borman read a small prayer for his church. He had been scheduled
to participate in a service at St. Christopher's Episcopal Church near
Seabrook, Texas, but due to the Apollo 8 flight he was unable to.
A fellow parishioner and engineer at Mission Control, Rod Rose,
suggested that Borman read the prayer which could be recorded and then
replayed during the service.[19][40]
Earthrise[edit]
Main article: Earthrise
When the spacecraft came out from behind the
MoonMoon for its fourth pass
across the front, the crew witnessed "Earthrise" for the first time in
human history (NASA's
Lunar Orbiter 1Lunar Orbiter 1 took the very first picture of
an
EarthriseEarthrise from the vicinity of the Moon, on August 23, 1966).[41]
Anders saw the
EarthEarth emerging from behind the lunar horizon, and then
called in excitement to the others, taking a black-and-white
photograph as he did so. Anders asked Lovell for a color film and then
took Earthrise, a more famous color photo, later picked by Life
magazine as one of its hundred photos of the century.[42]
Due to the synchronous rotation of the
MoonMoon about the Earth, Earthrise
is not generally visible from the lunar surface.
EarthriseEarthrise is
generally only visible when orbiting the Moon, other than at selected
places near the Moon's limb, where libration carries the Earth
slightly above and below the lunar horizon.
Anders continued to take photographs while Lovell assumed control of
the spacecraft so Borman could rest.[42] Despite the difficulty
resting in the cramped and noisy spacecraft, Borman was able to sleep
for two orbits, awakening periodically to ask questions about their
status.[42] Borman awoke fully, however, when he started to hear his
fellow crew members make mistakes. They were beginning to not
understand questions and would have to ask for the answers to be
repeated. Borman realized that everyone was extremely tired from not
having a good night's sleep in over three days. He ordered Anders and
Lovell to get some sleep and that the rest of the flight plan
regarding observing the
MoonMoon be scrubbed. At first Anders protested
saying that he was fine, but Borman would not be swayed. At last
Anders agreed as long as Borman would set up the camera to continue to
take automatic shots of the Moon. Borman also remembered that there
was a second television broadcast planned, and with so many people
expected to be watching he wanted the crew to be alert. For the next
two orbits Anders and Lovell slept while Borman sat at the helm. On
subsequent Apollo missions, crews would avoid this situation by
sleeping on the same schedule.

As they rounded the
MoonMoon for the ninth time, the second television
transmission began. Borman introduced the crew, followed by each man
giving his impression of the lunar surface and what it was like to be
orbiting the Moon. Borman described it as being "a vast, lonely,
forbidding expanse of nothing".[43] Then, after talking about what
they were flying over, Anders said that the crew had a message for all
those on Earth. Each man on board read a section from the Biblical
creation story from the
BookBook of Genesis. Borman finished the broadcast
by wishing a Merry Christmas to everyone on Earth. His message
appeared to sum up the feelings that all three crewmen had from their
vantage point in lunar orbit. Borman said, "And from the crew of
Apollo 8, we close with good night, good luck, a Merry Christmas and
God bless all of you—all of you on the good Earth."[44]
The only task left for the crew at this point was to perform the
Trans-
EarthEarth Injection (TEI), which was scheduled for 2½ hours
after the end of the television transmission. The TEI was the most
critical burn of the flight, as any failure of the SPS to ignite would
strand the crew in lunar orbit, with little hope of escape. As with
the previous burn, the crew had to perform the maneuver above the far
side of the Moon, out of contact with Earth.
The burn occurred exactly on time. The spacecraft telemetry was
reacquired as it re-emerged from behind the
MoonMoon at 89 hours,
28 minutes, and 39 seconds, the exact time calculated. When
voice contact was regained, Lovell announced, "Please be informed,
there is a Santa Claus", to which Ken Mattingly, the current CAPCOM,
replied, "That's affirmative, you are the best ones to know."[45] The
spacecraft began its journey back to
EarthEarth on December 25, Christmas
Day.
Unplanned manual re-alignment[edit]
Later, Lovell used some otherwise idle time to do some navigational
sightings, maneuvering the module to view various stars by using the
computer keyboard. However, he accidentally erased some of the
computer's memory, which caused the Inertial Measurement Unit (IMU) to
think the module was in the same relative position it had been in
before lift-off and fire the thrusters to "correct" the module's
attitude.[18]
Once the crew realized why the computer had changed the module's
attitude, they realized they would have to re-enter data that would
tell the computer its real position. It took Lovell ten minutes
to figure out the right numbers, using the thrusters to get the stars
RigelRigel and
SiriusSirius aligned, and another 15 minutes to enter the
corrected data into the computer.[36]
Sixteen months later, Lovell would once again have to perform a
similar manual re-alignment, under more critical conditions, during
the
Apollo 13Apollo 13 mission, after that module's IMU had to be turned off to
conserve energy. In his 1994 book, Lost Moon: The Perilous Voyage of
Apollo 13, Lovell wrote, "My training [on Apollo 8] came in handy!" In
that book he dismissed the incident as a "planned experiment",
requested by the ground crew.[36] In subsequent interviews Lovell has
acknowledged that the incident was an accident, caused by his
mistake.[18][19]
Cruise back to
EarthEarth and re-entry[edit]

Reentry, December 27, 1968, photographed from a
KC-135KC-135 at 40,000 feet

The cruise back to
EarthEarth was mostly a time for the crew to relax and
monitor the spacecraft. As long as the trajectory specialists had
calculated everything correctly, the spacecraft would re-enter
two-and-half days after TEI and splashdown in the Pacific.
On Christmas afternoon, the crew made their fifth television
broadcast.[46] This time they gave a tour of the spacecraft, showing
how an astronaut lived in space. When they finished broadcasting they
found a small present from
Deke SlaytonDeke Slayton in the food locker: a real
turkey dinner with stuffing, in the same kind of pack that the troops
in Vietnam received.[47] Another Slayton surprise was a gift of three
miniature bottles of brandy, that Borman ordered the crew to leave
alone until after they landed. They remained unopened, even years
after the flight.[48] There were also small presents to the crew from
their wives. The next day, at about 124 hours into the mission,
the sixth and final TV transmission showed the mission's best video
images of the earth, in a four-minute broadcast.[49]

Command Module on the deck of USS Yorktown

After two uneventful days the crew prepared for re-entry. The computer
would control the re-entry and all the crew had to do was put the
spacecraft in the correct attitude, blunt end forward.[50] If the
computer broke down, Borman would take over.[50]
Once the Command Module was separated from the Service Module, the
astronauts were committed to re-entry.[50] Six minutes before
they hit the top of the atmosphere, the crew saw the
MoonMoon rising above
the Earth's horizon, just as had been predicted by the trajectory
specialists.[51] As they hit the thin outer atmosphere they noticed it
was becoming hazy outside as glowing plasma formed around the
spacecraft. The spacecraft started slowing down and the deceleration
peaked at 6 g (59 m/s2).[22] With the computer controlling
the descent by changing the attitude of the spacecraft, Apollo 8
rose briefly like a skipping stone before descending to the ocean. At
30,000 feet (9.1 km) the drogue parachute stabilized the
spacecraft and was followed at 10,000 feet (3.0 km) by the three
main parachutes. The spacecraft splashdown position was officially
reported as 8°8′N 165°1′W﻿ / ﻿8.133°N 165.017°W﻿ /
8.133; -165.017﻿ (
Apollo 8Apollo 8 estimated splashdown) in the North
Pacific Ocean south of Hawaii.[4]
When it hit the water, the parachutes dragged the spacecraft over and
left it upside down, in what was termed Stable 2 position.[22]
About six minutes later the Command Module was righted into its normal
apex-up splashdown orientation by the inflatable bag uprighting
system.[22] As they were buffeted by a 10-foot (3.0 m) swell,
Borman was sick, waiting for the three flotation balloons to right the
spacecraft.[25] It was 43 minutes after splashdown before the
first frogman from USS Yorktown arrived, as the spacecraft had
landed before sunrise.[22] Forty-five minutes later, the crew was
safe on the deck of the aircraft carrier.[22][51]
Historical importance[edit]
Apollo 8 came at the end of 1968, a year that had seen much
upheaval in the United States and most of the world.[52] Even though
the year saw political assassinations, political unrest in the streets
of Europe and America, and the Prague Spring, Time magazine chose the
crew of Apollo 8 as its Men of the Year for 1968, recognizing
them as the people who most influenced events in the preceding
year.[52] They had been the first people ever to leave the
gravitational influence of the
EarthEarth and orbit another celestial
body.[53] They had survived a mission that even the crew themselves
had rated as only having a fifty-fifty chance of fully succeeding. The
effect of Apollo 8 can be summed up by a telegram from a
stranger, received by Borman after the mission, that simply stated,
"Thank you Apollo 8. You saved 1968."[54]
One of the most famous aspects of the flight was the
EarthriseEarthrise picture
that was taken as they came around for their fourth orbit of the
Moon.[55] This was the first time that humans had taken such a picture
whilst actually behind the camera, and it has been credited with a
role in inspiring the first
EarthEarth Day in 1970.[56] It was selected as
the first of Life magazine's 100 Photographs That Changed the
World.[57]
Apollo 11Apollo 11 astronaut Michael Collins said, "Eight's
momentous historic significance was foremost";[58] while many space
historians, such as Robert K. Poole, see
Apollo 8Apollo 8 as the most
historically significant of all the Apollo missions.[55]
The mission was the most widely covered by the media since the first
American orbital flight,
Mercury-Atlas 6Mercury-Atlas 6 by
John GlennJohn Glenn in 1962. There
were 1200 journalists covering the mission, with the
BBCBBC coverage
being broadcast in 54 countries in 15 different languages. The Soviet
newspaper
PravdaPravda featured a quote from Boris Nikolaevich Petrov,
Chairman of the Soviet
InterkosmosInterkosmos program, who described the flight
as an "outstanding achievement of American space sciences and
technology".[59] It is estimated that a quarter of the people alive at
the time saw—either live or delayed—the Christmas Eve transmission
during the ninth orbit of the Moon.[60] The
Apollo 8Apollo 8 broadcasts won an
Emmy Award, the highest honor given by the Academy of Television Arts
& Sciences.[61]

Madalyn Murray O'Hair, an atheist, later caused controversy by
bringing a lawsuit against
NASANASA over the reading from Genesis.[62]
O'Hair wished the courts to ban American astronauts—who were all
government employees—from public prayer in space.[62] Though the
case was rejected by the
Supreme Court of the United StatesSupreme Court of the United States for lack
of jurisdiction,[63] it caused
NASANASA to be skittish about the issue of
religion throughout the rest of the Apollo program. Buzz Aldrin, on
Apollo 11, self-communicated Presbyterian Communion on the surface of
the
MoonMoon after landing;[64] he refrained from mentioning this publicly
for several years, and only obliquely referred to it at the time.[64]
In 1969, the
United States Postal ServiceUnited States Postal Service issued a postage stamp
(
Scott catalogueScott catalogue #1371) commemorating the Apollo 8 flight around
the Moon. The stamp featured a detail of the famous photograph of the
EarthriseEarthrise over the
MoonMoon taken by Anders on Christmas Eve, and the
words, "In the beginning God ..."[65] Just 18 days after the
crew's return to Earth, they were featured during the 1969 Super Bowl
pre-game show reciting the
Pledge of AllegiancePledge of Allegiance prior to the national
anthem being performed by Anita Bryant.[66]
SpacecraftSpacecraft location[edit]
In January 1970, the spacecraft was delivered to Osaka, Japan, for
display in the U.S. pavilion at Expo '70.[67][68] It is now displayed
at the Chicago Museum of Science and Industry, along with a collection
of personal items from the flight donated by Lovell and the space suit
worn by Frank Borman.[69] Jim Lovell's
Apollo 8Apollo 8 space suit is on
public display in the Visitor Center at NASA's Glenn Research
Center.[70][71] Bill Anders's space suit is on display at the Science
Museum in London, United Kingdom.[72]
In popular culture[edit]
Apollo 8's historic mission has been shown and referred to in
several forms, both documentary and fiction. The various television
transmissions and 16 mm footage shot by the crew of Apollo 8 was
compiled and released by
NASANASA in the 1969 documentary, Debrief: Apollo
8, which was hosted by Burgess Meredith.[73] In addition, Spacecraft
Films released, in 2003, a three-disc DVD set containing all of NASA's
TV and 16 mm film footage related to the mission including all TV
transmissions from space, training and launch footage, and motion
pictures taken in flight.[74] Portions of the Apollo 8 mission
can be seen in the 1989 documentary For All Mankind, which won the
Grand Jury Prize Documentary at the Sundance Film Festival. The
television series
American ExperienceAmerican Experience aired a documentary, "Race to
the Moon", in 2005 during season 18.[75] The
Apollo 8Apollo 8 mission was
well-covered in the 2007 British documentary In the Shadow of the
Moon.[76]
Portions of the Apollo 8 mission are dramatized in the 1998
miniseries From the
EarthEarth to the
MoonMoon episode "1968".[77] The S-IVB
stage of Apollo 8 was also portrayed as the location of an alien
device in the 1970 UFO episode "Conflict".[78]
The
Apollo 8Apollo 8 mission was also featured in the Discovery channel's
6-part documentary series When We Left Earth: The
NASANASA Missions (Part
3, "Landing the Eagle"). All three astronauts were featured in this
documentary, telling the story of their historic mission to the Moon
in their own words.
Footage of
Apollo 8Apollo 8 appears in the Dawn of the Planet of the Apes
movie. A clip of
Frank BormanFrank Borman is shown on the news on TV in the
background whilst the news covered the first manned mission to Mars.
Apollo 8's Lunar
OrbitOrbit Insertion One was Chronicled with actual
recordings in the song "The Other Side" on the album The Race for
Space by the band Public Service Broadcasting.
See also[edit]

List of Apollo astronauts
Space Race

Notes[edit]

^ SPS is the rocket engine of the SM. RCS are the small thrusters on
its side.

References[edit]
This article incorporates public domain material from
websites or documents of the National Aeronautics and Space
Administration.

Colonization of the Moon
Exploration of the Moon
Google Lunar X Prize
List of Apollo astronauts
List of lunar probes
List of artificial objects on the Moon
List of missions to the Moon
Lunar rover
MoonMoon landing